These studies deal primarily with influences of age on the biochemistry of hormone-sensitive adenylate cyclase in a variety of tissues. The purpose of these studies is to explore the mechanisms of age-related alterations of hormone responsiveness and biological membranes, with special emphasis on the relationship between adenylate cyclase and hormone receptors. Other aspects include ongoing literature review of the field of aging and hormones in general and of certain aspects of clinical medicine as they relate to aging and endocrinology.